Problems installing HA onto Raspberry Pi 3B+

Hi all,

I am a bit of a Pi-noob so please be kind.

I am trying to install HA onto a Pi 3b+ but having no luck whatsoever. I have followed the standard install guidance (https://www.home-assistant.io/getting-started/), I have tried both 32 and 64 bit versions of the image. But every time I start the pi, I get a couple of green flashes with the red light but then just a constant red light and nothing else.

There is no apparent ethernet activity (I have tried multiple cables) and the pi doesn’t appear in the list of connected devices on my router. I have tried 2 different SD cards, and have tried two separate computers.

When I use Raspberry Pi Imager to write the Debian OS to an SD card, this works fine on both SD cards and the Pi loads as expected. It just seems that no matter what I do, I can’t get either of the HA images to work.

Any help would be greatly appreciated, I’m tearing my hair out!!

Thanks
Ross